cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A259654 a(n) = prime(n)^prime(n) - prime(n)^n.

Original entry on oeis.org

2, 18, 3000, 821142, 285311509560, 302875101765444, 827240261885926425504, 1978419655660296605560938, 20880467999847912032553880249104, 2567686153161211134561828214310308893183268, 17069174130723235958610643029033906279148329600
Offset: 1

Views

Author

Ilya Gutkovskiy, Jul 02 2015

Keywords

Crossrefs

Programs

  • Magma
    [NthPrime(n)^NthPrime(n)-NthPrime(n)^n: n in [1..12]]; // Vincenzo Librandi, Jul 03 2015
    
  • Mathematica
    Table[Prime[n]^Prime[n] - Prime[n]^n, {n, 1, 10}]
    #[[1]]^#[[1]]-#[[1]]^#[[2]]&/@Table[{Prime[n],n},{n,15}] (* Harvey P. Dale, Nov 10 2016 *)
  • PARI
    a(n,p=prime(n))=p^p - p^n \\ Charles R Greathouse IV, Jul 22 2016

Formula

a(n) = A051674(n) - A062457(n).

A259923 a(n) = prime(n)^pi(n).

Original entry on oeis.org

1, 3, 25, 49, 1331, 2197, 83521, 130321, 279841, 707281, 28629151, 69343957, 4750104241, 6321363049, 10779215329, 22164361129, 2488651484819, 3142742836021, 406067677556641, 645753531245761, 806460091894081, 1517108809906561, 186940255267540403, 350356403707485209, 760231058654565217
Offset: 1

Views

Author

Ilya Gutkovskiy, Jul 09 2015

Keywords

Examples

			For n = 1, a(1) = 2^0 = 1.
		

Crossrefs

Programs

  • Magma
    [NthPrime(n)^#PrimesUpTo(n): n in [1..30]]; // Vincenzo Librandi, Aug 03 2015
  • Mathematica
    Table[Prime[n]^PrimePi[n], {n, 1, 25}]
  • PARI
    vector(30, n, prime(n)^primepi(n)) \\ Michel Marcus, Jul 09 2015
    

Formula

a(n) = A000040(n)^A000720(n).
a(n) ~ (n * log n)^(n/log(n)), by the prime number theorem.

A276650 Primes of the form prime(k)^k - PrimePi(k).

Original entry on oeis.org

2, 2399, 1801152661459, 73885357344138503765443
Offset: 1

Views

Author

Robert C. Lyons, Sep 09 2016

Keywords

Comments

Searched up to k = 1000.
No additional entries up to k = 5000. - Ethan Beihl, Oct 15 2016
No additional entries up to k = 15000. - Tyler Busby, Mar 12 2024

Examples

			2 is in the sequence because 2 is prime and 2 = prime(1)^1 - PrimePi(1) = 2^1 - 0.
2399 is in the sequence because 2399 is prime and 2399 = prime(4)^4 - PrimePi(4) = 7^4 - 2.
1801152661459 is in the sequence because 1801152661459 is prime and 1801152661459 = prime(9)^9 - PrimePi(9) = 23^9 - 4.
73885357344138503765443 is in the sequence because 73885357344138503765443 is prime and 73885357344138503765443 = prime(14)^14 - PrimePi(14) = 43^14 - 6.
		

Crossrefs

Programs

  • Mathematica
    Select[Map[Prime[#]^# - PrimePi@ # &, Range@ 1500], PrimeQ] (* Michael De Vlieger, Sep 26 2016 *)
  • SageMath
    max_n = 20
    seq = []
    for n in range(1, max_n+1):
        p = nth_prime(n)^n - prime_pi(n)
        if is_prime(p):
            seq.append(p)
    print(seq)
Previous Showing 51-53 of 53 results.